Except for the extra wheels in the back, your truck sounds pretty similar to mine. You will love the SBC.
I'm curious, is your timing still at the stock setting or have you bumped it up. I got the 370s, but no DVs yet. I haven't installed them yet because I want to advance the timing to help control the EGTs. I'm a little worried about too much smoke as well. Did your mileage suffer?